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Biomedical subjects

K Pringle

Publications and source records attributed to K Pringle.

16 recordsLinked to original sources
PubMed1992

Tissue heating effect of pulsed Doppler ultrasound in the live fetal lamb brain.

A series of experiments in fetal lambs investigated the heating effects of pulsed Doppler ultrasound on fetal brain tissue. In dead lamb brain, tissue heating was observed at the skull bone-to-brain interface. Minimal or no temperature rise was found in the live lamb, suggesting that the intact circulation conducts away any potential heating. The choice of animal model and the state of the circulation influence the results obtained. This will of course have implications for clinical practice.

Animals↗
PubMed1991

Endoscopic fetal surgery by excimer laser. An experimental study in premature lambs.

Fetal malformations are detected early in pregnancy by means of ultrasound challenging fetal therapy. While open fetal surgery has been preformed during preliminary clinical trials we evaluated fetoscopic therapy avoiding laparotomy and uterotomy. We used a laser fibre (900 mu) which was introduced into the uterus by an endoscope. During animal experiments in five fetal lambs with a gestational age of 120-122 days we used an excimer laser (Technolas, x) with a wave-length of 308 nm. Laser incisions were compared with the conventional cutting technique using a scapel. During histological evaluation the tissue effect was morphometricly analysed. The zone of devitalisation was characterized by pycnosis of the nuclei and in a change of cytoplasma volume. The excimer laser incisions using a frequency of 40 HZ had a mean zone of devitalisation of 50.3 +/- 4.5 mu. Using the excimer laser with a frequency of 10 HZ we found a tissue alteration of only 11.2 +/- 3.4 mu. The incisions by scapel showed a extended traumatisation with a mean tissue effect of 153.2 +/- 16.3 mu. From these results we conclude, that endoscopic surgery may be come a usefull additional tool for fetal therapy.

Animals↗
PubMed1991

An approach to fetal surgery: endoscopic use of excimer laser.

Recent progress in the area of prenatal diagnosis by means of ultrasound forces the improvement of surgical techniques for intra-uterine fetal therapy. By the use of short, intense pulses of ultraviolet laser light (20-200 ns long) a photoablation of defined samples of biological tissue is performed with no substantial thermal side effects. The experimental set-up applied in this study included endoscopic operation on five fetal lambs. Macroscopically, a sharp edge in the incision area was observed at both prechosen laser frequencies of 10 and 40 Hz. The clinical application of pulsed ultraviolet laser systems with the characteristics of guided photoablation and atraumatic incisions avoiding thermal side-effects opens new perspectives for fetal surgery.

Animals↗
PubMed1990

[Laser spectroscopic assessment of induced hyperoxia--an animal experiment in lambs].

The noninvasive determination of biochemical parameters has become an important aspect of intensive care medicine. The newly developed monitors for laser reflectometry provide the possibility of spectroscopic monitoring. The equipment consists of a near-infrared data collection unit and a personal computer. The four laser diodes emit light at wavelengths of 775, 805, 845 and 904 nm. By analyzing the changes in optical density during laser irradiation of biological tissue, information is obtained about the relative changes in the concentration of hemoglobin and the blood volume. In animal experiments with ten fetal lambs we evaluated the reliability of near infrared laser spectroscopy. Fetal hyperoxia was achieved by means of an extracorporeal circuit with interposition of a membrane oxygenator (0.8 m2, Scimed). During the induced hyperoxia the laser spectroscopic tracings showed a rise in the HbO2 signal with a synchronous decrease in the HbR signal. Additionally, the spectroscopic pattern showed a characteristic initial rise in the intracerebral blood volume, which stabilized after 4 minutes. We found a significant correlation between the intermittently measured PO2 values of the arterial blood samples and the laser spectroscopic HbO2 and HbR signals (r = 0.87, and r = -0.82, respectively; p less than 0.001). Furthermore, hyperoxia was indicated by the laser system with a short lag time. We conclude that laser spectroscopy is a reliable method with a high potential for clinical routine use in intensive care, as it provides noninvasive continuous information at comparatively low costs using portable monitors.

Animals↗
PubMed1988

Miliary pulmonary neuroblastoma. A risk of autologous bone marrow transplantation?

A case of miliary pulmonary neuroblastoma is described which occurred 8 months after autologous bone marrow transplantation for Stage IV neuroblastoma. The patient, a 4-year-old boy had pulmonary symptoms at this time. Disseminated metastatic disease was found, but there was no tumor at the primary site. This unusual pattern of relapse suggests that the patient's disseminated disease was related to infusion of malignant cells at the time of transplantation.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1986

Pregnancy outcome following ultrasound diagnosis of fetal urinary tract anomalies and/or oligohydramnios.

We have reviewed 49 pregnancies with ultrasound evidence of fetal urinary tract anomalies and/or oligohydramnios. A surprisingly large number of fetuses with urinary tract obstruction had significant other anomalies. Fetuses with urinary tract obstruction, but a normal amount of amniotic fluid, did well without in utero intervention; however, those with oligohydramnios or polyhydramnios fared poorly. Longer periods of oligohydramnios in fetuses with urinary tract obstruction seemed to be associated with pulmonary hypoplasia and renal dysplasia. Oligohydramnios without urinary tract obstruction complicated 28 pregnancies; there were only 10 survivors. Diagnostic pitfalls are described.

Amniotic Fluid↗
PubMed1986

In utero bladder diversion--problems with patient selection.

Based upon the concept that an obstruction-maldevelopment sequence is reversible after diversion, it has been suggested that the fetus with a bladder outlet obstruction is a potential candidate for in utero intervention. We report an infant who had both renal and pulmonary dysplasia at birth despite a technically successful diversion at 22 weeks' gestation. The poor outcome suggests that the organ damage either occurs so early that it precludes corrective surgery, or that the maldevelopment is not the result of obstruction, but rather a primary mesodermal defect.

Abdomen↗
PubMed1986

Antenatal diagnosis and palliative treatment of nonimmune hydrops fetalis secondary to pulmonary extralobar sequestration.

The causes of nonimmune hydrops fetalis are multiple. Despite the fact that many of the affected fetuses are otherwise free of fatal abnormalities, many die in the neonatal period from pulmonary hypoplasia. The overall perinatal mortality is as high as 80%. Extralobar pulmonary sequestration is an abnormal and nonaerated mass of extra pulmonary-located lung tissue supplied by a systemic artery, and is a rare cause of nonimmune hydrops. In the only two published reports, the hydropic fetuses died at birth. Both the first antenatal diagnosis of this disorder and the first attempt at palliative in utero therapy are reported herein. Though the fetus ultimately delivered prematurely and succumbed, treatment was associated with both subjective improvements in fetal well-being and objective reversal of the hydrops.

Adult↗
PubMed1983

Glucose-6-phosphatase as a marker for tumors of liver and kidney origin.

Glucose-6-phosphatase is primarily a liver and kidney enzyme. This enzyme was studied in various tumors, however, glucose-6-phosphatase activity was found only in tumors of liver, kidney, or adrenal origin. Glucose-6-phosphatase activity was useful in identifying the tissue origin of extrarenal Wilms'. Metastatic tumors within the liver or kidney that originated from other tissues did not have glucose-6-phosphatase activity. Therefore, it is suggested that glucose-6-phosphatase can be used as a specific enzyme marker for tumors of liver and kidney origin.

Carcinoma, Hepatocellular↗
PubMed1982

Fetal treatment 1982.

Explore the source record for details and available documents.

Congenital Abnormalities↗
PubMed1980

Splenic embolization.

While transcatheter embolization of the spleen has shown promise in the treatment of a wide spectrum of disorders, the incidence of serious complications with this technique has limited its use as an alternative to operative splenectomy. In our institution 41 patients were treated with a modified technique involving partial splenic embolization, careful antibiotic prophylaxis, and adequate pain control. There was no mortality and only few instances of clinically significant complications: a splenic abscess in one patient, pancreatitis in one patient, severe pleural effusions in two patients, and pneumonia in five patients.

Adolescent↗
PubMedDate not supplied

[The influence of umbilical cord compression on the fetal brain--an animal experiment using laser spectroscopy].

In order to evaluate the influence on the fetal brain due to compression of the umbilical cord biochemical and biophysical changes were traced during defined occlusions of 60 sec by means of NIR laser spectroscopy. Synchronously blood samples were drawn intermittently from a catheter positioned in the A. carotis and analysed for blood gases. The saturation values measured in the fetal blood correlated significantly with the dates of the HbO2 tracing of the NIR-system (r = 0.81, p less than 0.001). After induced occlusion of the umbilical cord a reproducible pattern of the NIR tracing occurred. While an immediate fall in HbO2 occurred, a synchronous rise in desaturated Hb was observed. For the changes of the cytochrome aa3 we detected a minor decrease that occurred with a lag time. Additionally there was an indication of a major change of blood volume as the total Hb content augmented during each compression. We concluded: Changes of Hb-saturation in the fetal blood are immediately indicated by NIR-laser spectroscopy. During cord occlusion of 60 sec. the intracellular oxygenation decrease only after a significant lag time and are reversible and furthermore it leads to a reproducible change of intracerebral blood volume.

Animals↗